1. Field of the invention
The present invention relates to a ladder filter, and more particularly to a ladder filter which is used in a communicating machine, a transceiver, and a cordless telephone.
2. Description of Related Art
Conventionally, as a ladder filter for eliminating noise, a rudder filter wherein piezoresonators which are connected in series and piezoresonators which are connected in parallel are connected alternately between an input terminal and an output terminal is well known.
In the conventional ladder filter, all internal components such as the piezoresonators and the input terminal and the output terminal are stacked together contained in a housing. Thus, the filter is tall and results in useless space when the filter is mounted on a printed circuit board and installed in an electronic machine. Also, the structure of such a filter is not suitable for automatic assembly.